LinkedTransferQueue getWaitingConsumerCount() method in Java with Examples
The getWaitingConsumerCount() method in LinkedTransferQueue is a specialized utility that provides insight into the number of consumer threads that are currently waiting to receive elements from the queue. The above method is particularly useful for monitoring and debugging concurrent applications where understanding the state of consumer threads can help diagnose performance bottlenecks or synchronization issues.
The getWaitingConsumerCount() method provides a snapshot of consumer threads waiting for elements, aiding in understanding application load and behaviour. It helps gauge blocked threads in a LinkedTransferQueue. The non-exact count is an estimate due to race conditions and timing issues.
Syntax:
public int getWaitingConsumerCount()
Parameters:
The getWaitingConsumerCount() method does not take any parameters.
Return Value:
The method returns an int value estimating the number of consumer threads waiting to receive elements from the queue. The count is not exact due to the concurrent nature of the operations and potential race conditions.
Example:
Here's an example of a program using one producer and three consumers with a LinkedTransferQueue. The producer sends three messages, and the consumer threads call take() to receive the messages. The first consumer to call take() will receive the latest message, and the exact distribution of messages can vary between different executions of the program.
FileName:GetWaitingConsumerCountExample.java
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.TimeUnit;
public class GetWaitingConsumerCountExample {
public static void main(String[] args) {
LinkedTransferQueue
long endTime = System.currentTimeMillis() + 10000; // Run for 10 seconds
// Producer thread
new Thread(() -> {
try {
// Producing three messages
for (int i = 1; i <= 3; i++) {
String message = "Message " + i;
System.out.println("Producing: " + message);
queue.put(message);
TimeUnit.SECONDS.sleep(2); // Simulate some delay
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
// Consumer threads
for (int i = 0; i < 3; i++) {
new Thread(() -> {
try {
while (System.currentTimeMillis() < endTime) {
String message = queue.take();
System.out.println("Consumer " + Thread.currentThread().getId() + " received: " + message);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
// Monitor waiting consumer count
new Thread(() -> {
try {
while (System.currentTimeMillis() < endTime) {
int waitingCount = queue.getWaitingConsumerCount();
System.out.println("Number of waiting consumers: " + waitingCount);
TimeUnit.SECONDS.sleep(1); // Check every second
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
Output:
Producing: Message 1 Number of waiting consumers: 2 Consumer 13 received: Message 1 Number of waiting consumers: 3 Producing: Message 2 Consumer 14 received: Message 2 Number of waiting consumers: 3 Number of waiting consumers: 3
Need of getWaitingConsumerCount() method
The `getWaitingConsumerCount()` method is crucial for managing consumer threads in a concurrent environment, particularly in multi-threaded applications. It helps in thread management, concurrency control, performance monitoring, dynamic load balancing, and responsive design. By understanding the number of waiting consumers, developers can make informed decisions about resource allocation, task distribution, and load-balancing strategies. High numbers of waiting consumers can indicate bottlenecks or inefficiencies in task distribution or resource management. Therefore, `getWaitingConsumerCount()` is essential for maintaining efficient concurrency management, optimizing performance, and ensuring responsiveness in multi-threaded applications.